Oil prices may finally hit $100 a barrel this week in what could be the most volatile commodity roller-coaster ride in years.

It's a situation one analyst likened to a high-stakes poker game. A showdown between traders who believe the price will rise and those who believe it will fall could bring both results — a brief taste of $100, followed by a rapid sell-off.

Lehman Brothers chief energy economist Edward Morse said in a report late last week that more than 350,000 oil futures contracts must be sold before they expire on Friday.

But a slew of options to buy oil at $100 a barrel will expire worthless on Tuesday if oil prices don't reach that level.

"The market may be set up to test $100 by Tuesday," Morse said. "It also appears poised to sell off — perhaps strongly — soon afterward."

Crude prices briefly surpassed $98 a barrel in the middle of last week on supply fears but fell to the mid-$90 range after the federal government unveiled a smaller-than-expected drop in U.S. inventories. Prices slipped further Thursday after Federal Reserve Chairman Ben Bernanke warned that the U.S. economy will slow in the coming months as high energy prices add inflationary pressure.

Throughout last week, traders pointed to various other factors that pushed prices near $100, including the brief evacuation of North Sea oil platforms because of a storm.

By Friday, production had resumed at the platforms, but prices were nearly 50 cents higher in intraday trading than Thursday's $95.46 close on the New York Mercantile Exchange. Oil closed Friday at $96.32.

In a market marked by tight supply and growing demand — as well as geopolitical tensions, the weak dollar and itchy financial players — fingers point to otherwise minor incidents to explain price movement.

"Anything that can be hyped will be hyped," said Kyle Cooper, an oil analyst with Citigroup in Houston.

Expiration date looms

Lehman Brothers' Morse said in the report that the Dec. 7 futures contract for West Texas Intermediate crude — the U.S. benchmark — will expire Friday, and 360,000 contracts remained outstanding. Most of those contracts are held by financial players in the oil market and must be sold by the expiration date, Morse said.

A futures contract is an exchange-traded instrument that requires delivery of a commodity at a specific price on a specific date.

"Presumably, market participants know that the exits are going to be crowded over the next few days if they do not sell their positions soon," he said.

Adding fuel is the West Texas Intermediate options market on the Nymex, where 42,000 Dec. 7 call options for $100 are set to expire Tuesday.

A call option gives an owner the right to buy shares of an underlying security — in this case, a futures contract — at a specific price for a fixed period of time.

An option to buy at $100 a barrel will only be profitable if oil costs more than that sometime before the option expires.

So those 42,000 call options will "expire worthless" on Tuesday if oil doesn't reach $100 a barrel by then.

"Perhaps, before Tuesday, holders of these calls will attempt to push oil to $100 in a last effort to force these options into the money," he said.

Eric Wittenauer, an analyst with A.G. Edwards & Sons, said 42,000 call options at $100 indicated that the holders expect they will be able to exercise them at that price.

"I think it's a logical argument that someone's going to have a lot of money on the line and potentially want to drive the price up to $100 and above," he said. "If you break through $100 and tack on some more, you make that much more profit on your positions."

Morse said speculators could back off and take profits before a barrel hits $100, but the price most likely will make "a serious run at $100" by Tuesday and perhaps reach $105 before selling pressure ensues.

Then, with the contracts that must be sold by Friday, the rush to sell "may be stronger than anything the oil market has seen in several years," Morse said.

He said prices could fall to the low $80 range by early December.

Cooper noted that in commodity markets, every long has a short — meaning for every person who bets prices will go up, others bet they will fall. Investors owning calls may buy futures contracts to push prices higher, while those who sold the call options sell futures to keep prices below the call price.